{"answers":{"affected":"It affects 2 products.","exploited":"There is no known exploitation of CVE-2021-3491 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2021-3491 is a high-severity vulnerability in Canonical Ubuntu Linux, published on 4 Jun 2021. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2021-3491 and fix it if it is affected.\n\nWhat it is: CVE-2021-3491 is a high-severity vulnerability in Canonical Ubuntu Linux, published on 4 Jun 2021. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2021-3491 in the wild and no public exploit code.\n\nAffected product: Canonical Ubuntu Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2021-3491/ (Markdown: https://insights.sbomify.com/CVE-2021-3491/index.md)","id":"CVE-2021-3491","markdown":"https://insights.sbomify.com/CVE-2021-3491/index.md","name":"CVE-2021-3491","record":{"aliases":["A-190877100","DEBIAN-CVE-2021-3491","GHSA-q4c9-gg27-f3pq","PUB-A-190877100","UBUNTU-CVE-2021-3491"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["code_execution","privilege_escalation"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A bypass of MAX_RW_COUNT in io_uring PROVIDE_BUFFERS allows heap overflow and arbitrary code execution in the Linux kernel.","user_interaction":"not_required","vuln_class":"integer_overflow"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"canonical","cpe":[{"product":"ubuntu_linux","vendor":"canonical"},{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":7.8,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H","version":"3.1"},"cwes":[{"id":"CWE-787","name":"Out-of-bounds Write"},{"id":"CWE-131","name":"Incorrect Calculation of Buffer Size"}],"description":"The io_uring subsystem in the Linux kernel allowed the MAX_RW_COUNT limit to be bypassed in the PROVIDE_BUFFERS operation, which led to negative values being usedin mem_rw when reading /proc/\u003cPID\u003e/mem. This could be used to create a heap overflow leading to arbitrary code execution in the kernel. It was addressed via commit d1f82808877b (\"io_uring: truncate lengths larger than MAX_RW_COUNT on provide buffers\") (v5.13-rc1) and backported to the stable kernels in v5.12.4, v5.11.21, and v5.10.37. It was introduced in ddf0322db79c (\"io_uring: add IORING_OP_PROVIDE_BUFFERS\") (v5.7-rc1).","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"Linux kernel io_uring PROVIDE_BUFFERS MAX_RW_COUNT bypass","id":"CVE-2021-3491","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"canonical:ubuntu_linux","products":["canonical:ubuntu_linux","linux:linux_kernel"],"type":"integer_overflow","year":"2021"},"n_packages":0,"n_references":6,"next":{"headline":"Ubuntu linux kernel shiftfs file system double free vulnerability","id":"CVE-2021-3492"},"packages":[],"prev":{"headline":"Linux kernel eBPF bitwise ops ALU32 bounds tracking","id":"CVE-2021-3490"},"products":["Linux kernel"],"published":"2021-06-04","related":[{"cvss_score":9.8,"headline":"SaltStack Salt Authentication Bypass","id":"CVE-2020-11651","kev_date_added":"2021-11-03","published":"2020-04-30"},{"cvss_score":9.8,"headline":"OpenSMTPD Remote Code Execution","id":"CVE-2020-7247","kev_date_added":"2022-03-25","published":"2020-01-29"},{"cvss_score":9.8,"headline":"Exim Out-of-bounds Write","id":"CVE-2019-16928","kev_date_added":"2022-03-03","published":"2019-09-27"},{"cvss_score":9.8,"headline":"Exim Buffer Overflow","id":"CVE-2018-6789","kev_date_added":"2021-11-03","published":"2018-02-08"},{"cvss_score":9.8,"headline":"Oracle Java SE and Java SE Embedded Remote Code Execution","id":"CVE-2015-2590","kev_date_added":"2022-03-03","published":"2015-07-16"},{"cvss_score":9.8,"headline":"Oracle JRE Remote Code Execution","id":"CVE-2013-0422","kev_date_added":"2022-05-25","published":"2013-01-10"},{"cvss_score":9.8,"headline":"Oracle Java SE Runtime Environment (JRE) Arbitrary Code Execution","id":"CVE-2011-3544","kev_date_added":"2022-03-03","published":"2011-10-19"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2024-09-16","vendors":["Linux"]},"summary":"A bypass of MAX_RW_COUNT in io_uring PROVIDE_BUFFERS allows heap overflow and arbitrary code execution in the Linux kernel.","url":"https://insights.sbomify.com/CVE-2021-3491/"}